• Open your SQL Management Studio
• Right Click in you SQL connection
• Click in New Query
• Paste and execute :

USE master
GO
xp_readerrorlog 0, 1, N'Server is listening on',N'', NULL, NULL, N'asc'
GO

it should show you the SQL Server Port. If this dont show you the port, do the next.

• Use Windows key(start) + R
• Paste SQLServerManager15.msc and Enter
• Select SQL Server Network Configuration
• Select your SQL Server Instance
• Right Click in TCP/IP and select enable
• Do click again and select properties
• Select IP Addresses tab and go to the end
• If you know what port is free for use write it in TCP Port, apply changes and save, leap the next step and go to the end step.

• Use Windows key(start) + q
• find cmd and execute it with admin privileges.
• write netstat -ano | findstr *PORT*, replace *PORT* for a por number, default SQl use 4033 or 4034, try this port
• if dont appear a process listening in the console you can use it port in the previous step. Otherwise try another port.
• Do the previous step again and use that port in TCP Port

• Use Windows key(start) + R
• Paste SQLServerManager15.msc and Enter
• Select SQL Server Services and restar SQL Server and SQL Server Browser
• all ready, that is your SQL Server Port and you can use step 1 again.